Synthetic rutile is a man-made material used as an early imitation of diamond. It was introduced in the late 1940s and is made by flame fusion.
Properties
| Refractive index | 2.616 to 2.903 (o = 2.616, e = 2.903) |
|---|---|
| Birefringence | 0.287 |
| Optic character | Doubly refractive (uniaxial) |
| Dispersion | 0.33 |
| Specific gravity | 4.26 |
| Hardness (Mohs) | 6 to 6.5 |
| Crystal system | Tetragonal |
| Pleochroism | Not recorded |
| Absorption spectrum | Not diagnostic |
Published values. They change a little from stone to stone. Our tools do not model synthetic rutile yet. Sources: GIA · International Gem Society
In more detail
It has far more fire than diamond, and this intense fire easily gives it away. It is doubly refractive, so you see doubled facets and the inside can look blurry. It is often slightly yellowish. It is soft, so it scratches fairly easily and typically has rounded facet junctions.
Related terms
- Simulant: A simulant is a material that looks like a gem but has a different chemistry, structure and properties. Cubic zirconia, moissanite and glass are diamond simulants.
- Strontium titanate: Strontium titanate is a colorless man-made material used as an imitation of diamond. It became a popular diamond simulant in the 1950s.
- Flame fusion: Flame fusion grows synthetic crystals by dropping fine powder through a very hot flame. The melted drops build up a crystal on a pedestal below.
- Facet doubling: Facet doubling is the double image of facet edges seen through a strongly doubly refractive stone. It shows clearly in moissanite under a 10× loupe.
- Doubly refractive: A doubly refractive stone splits light into two rays that vibrate at right angles and travel at different speeds. Each ray has its own refractive index.
- Fire: Fire is the flashes of spectral color that a cut stone sends out. In our census, fire is the share of returned light whose colors leave more than 0.6° apart.